Hard disk drive (HDD) systems are being developed in which multiple read sensors read a single recorded track. In such an HD assembly, readback signals from multiple sensors can be processed jointly to yield an equalized signal with better signal to noise ratio than if only a single read sensor were used. Processing multiple readback signals, however, requires additional analog and digital circuitry, which in turn consumes more power than a comparable read channel processing only a single readback signal.
In some applications it may be desirable to revert to a low power mode utilizing only a single readback sensor by disabling additional circuitry associated with the second read sensor.